A simple pacing method to diagnose postero-anterior (clockwise) cavo-tricuspid isthmus block after radiofrequency ablation.

AIMS: Bidirectional block of the cavo-tricuspid isthmus (CTI) is a widely accepted endpoint for typical atrial flutter ablation, but its evaluation may be difficult, especially in the postero-anterior (clockwise) direction. The main goal was to evaluate pacing at the septal edge of the ablation line as an indicator of clockwise CTI block and as a predictor for flutter recurrence. METHODS AND RESULTS: In 94 patients undergoing flutter ablation, CTI block in the antero-posterior (counterclockwise) direction was determined by differential pacing from several levels of the anterior right atrial (RA). CTI block in the clockwise direction was evaluated by analysing electrograms (EGM) at the ablation line during differential pacing of the septal RA (differential septal pacing) or by anterior sequence of RA during pacing septal isthmus, next to the ablation line (septal CTI pacing). Ablation produced bidirectional block in 78% of the patients, unidirectional counterclockwise block in 9% and bidirectional conduction persisted in 13%. After follow-up (37 +/- 23 months), flutter recurrence occurred in 13% (48% if persistent conduction vs. 3% if bidirectional block, P < 0.001). During differential septal pacing, EGMs were difficult to interpret in 36% of the patients; in these cases, the diagnosis of CTI block or conduction in the clockwise direction was clearly established by using septal CTI pacing. CONCLUSION: Activation sequence of anterior RA during septal CTI pacing, next to the ablation line, is a reliable and simple method to diagnose clockwise CTI block and is associated with a low flutter recurrence.

Electroanatomic study of the left atrial insertion of an epicardial accessory pathway integrating the coronary sinus.

Endocardial electro-anatomic reconstruction of the left atrium and activation mapping defined a very large atrial accessory pathway insertion with a previously failed ablation attempt. Radiofrequency application inside the coronary sinus (CS), at a site with a sharp electrogram bridging atrial and ventricular electrograms abolished pathway conduction. The myocardium in the venous branches of the CS appeared to be responsible for this extraordinary atrial insertion area.

Atrial activation occurring immediately after successful cardioversion of atrial fibrillation.

BACKGROUND AND OBJECTIVE: Electrical defibrillation is very effective in interrupting atrial fibrillation (AF). However, its mechanism is not completely understood. We report our observations in patients subjected to external electriocardioversion (ECV) of atrial fibrillation and contrast them with recent theories about defibrillation mechanism. METHODS: In 13 consecutive patients transthoracic electrical cardioversion for AF was performed during an electrophysiological study (11 monophasic -200-360 J- and 9 biphasic shocks -50-150 J-). About 10-16 electrograms were obtained with multipolar catheters recording right atrium, coronary sinus, and right pulmonary artery. AF was defined by interelectrogram intervals and changing sequences among recordings, indicating complete lack of organization. We evaluated the presence of propagated activations immediately (<300 ms) after successful shocks (>or=1 discrete electrogram in all recordings). In unsuccessful shocks we evaluated changes in electrogram morphology (discrete/fragmented) and interelectrogram intervals before and after defibrillation. RESULTS: About 16/20 shocks terminated AF. In 6/16 one or two cycles of atrial activation were recorded just after the shock and before AF ended. In 10/16 AF was interrupted immediately after the shock. 4/20 shocks did not interrupt the arrhythmia. After these shocks, transient organization of recorded activity with longer interelectrogram cycle length and disappearance of fragmented activity were transiently observed. CONCLUSION: Our clinical findings in atrial defibrillation in vivo reproduce experimental data that show myocardial activations early after successful direct current shocks. These observations suggest that successful defibrillation depends not only on the immediate effects of the shock, but also on transient effects on electrophysiological properties of the myocardium, capable of interrupting persistent or reinitiated activations.

Taquicardia ventricular como manifestación clínica inicial de feocromocitoma / Ventricular tachycardia as initial presentation of pheochromocytoma

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[The superior vena cava as a site of ectopic foci in atrial fibrillation]. / La vena cava superior como inductora de fibrilación auricular de origen focal.

Radiofrequency catheter ablation of ectopic foci that trigger atrial fibrillation has been established as a curative method for patients with symptomatic paroxysmal atrial fibrillation. Although the majority of these foci are located in and around the pulmonary veins, other less common locations have been identified. Recognition that foci can lie outside the pulmonary veins is important for ensuring therapeutic success. The most frequently reported foci of ectopic activity outside the pulmonary veins are in the superior vena cava and the posterior wall of the left atrium. Here we report our experience with the ablation of ectopic foci located in the superior vena cava in patients with symptomatic paroxysmal atrial fibrillation.

La vena cava superior como inductora de fibrilación auricular de origen focal / The superior vena cava as a site of ectopic foci in atrial fibrillation

La ablación de focos auriculares precipitantes de fibrilación auricular se ha constituido como una técnica curativa para pacientes con fibrilación auricular paroxística sintomática. Aunque la mayoría de focos ha sido descrita en las venas pulmonares, se han identificado otras localizaciones que, aunque menos frecuentes, pueden ser de relevancia clínica en determinados pacientes. El reconocimiento de estas localizaciones durante un procedimiento de ablación es fundamental a la hora de planear el abordaje anatómico. La vena cava superior, junto con la pared posterior de la aurícula izquierda, suele ser la localización más frecuente de actividad ectópica fuera de las venas pulmonares. Presentamos nuestra experiencia de la ablación de focos ectópicos en la vena cava superior en pacientes con fibrilación auricular paroxística sintomática

Radiofrequency catheter ablation of ectopic foci that trigger atrial fibrillation has been established as a curative method for patients with symptomatic paroxysmal atrial fibrillation. Although the majority of these foci are located in and around the pulmonary veins, other less common locations have been identified. Recognition that foci can lie outside the pulmonary veins is important for ensuring therapeutic success. The most frequently reported foci of ectopic activity outside the pulmonary veins are in the superior vena cava and the posterior wall of the left atrium. Here we report our experience with the ablation of ectopic foci located in the superior vena cava in patients with symptomatic paroxysmal atrial fibrillation

Pyoderma gangrenosum complicating pacemaker implant.

A 70-year-old lady with diabetes and monoclonal gammopathy underwent pacemaker implant for 2:1 atrioventricular block. Within 7 days, a painful, infiltrating, necrotic lesion involved the implant area. Biopsy was compatible with pyoderma gangrenosum and corticosteroid treatment led to healing in 3 weeks.

[Atrial flutter: an update]. / Flúter auricular: perspectiva clínica actual.

Invasive electrophysiologic studies have changed the clinical outlook for patients with atrial flutter. Recognition of the reentrant circuit responsible for typical atrial flutter has led to the development of catheter ablation techniques that can prevent recurrence in >90% of cases. In addition, general understanding of atrial tachycardias has changed radically, such that ECG-based classifications are now obsolete. Atypical reentrant circuits associated with surgical scars or fibrotic areas in either atrium, which are indistinguishable from focal tachycardias on ECG, have been identified. These circuits also seem amenable to treatment by ablation. Recently, a new type of reentrant tachycardia that could be problematic in the future has emerged in patients who have undergone extensive left atrial ablation for the treatment of atrial fibrillation. These atypical circuits can be characterized using the mapping and entrainment techniques initially developed for typical flutter. In these cases, electroanatomical mapping, involving the construction of a virtual anatomical model of the atria, is extremely helpful. Despite the success of ablation, long-term prognosis is frequently overshadowed by the appearance of atrial fibrillation, which suggests that flutter and fibrillation share a common arrhythmogenic origin that is not modified by cavotricuspid isthmus ablation. In contrast with our clear electrophysiologic understanding of atrial flutter, little is known about the natural history of the condition because the literature has traditionally grouped patients with flutter and fibrillation together. Consequently, the complex relationship between the two arrhythmias has still to be clearly delineated. Primary prevention and preventing the development of atrial fibrillation after ablation remain outstanding clinical challenges.

Flúter auricular: perspectiva clínica actual / Atrial Flutter: an Update

Los estudios electrofisiológicos invasivos han cambiado la perspectiva clínica de los pacientes con flúter auricular. El conocimiento de la estructura del circuito de flúter típico ha permitido desarrollar técnicas de ablación con catéter que eliminan las recidivas en > 90% de los casos. También ha cambiado el concepto global de las taquicardias auriculares, lo que ha hecho obsoletas las clasificaciones basadas en el electrocardiograma. Se han demostrado circuitos reentrantes atípicos basados en cicatrices quirúrgicas o en zonas fibróticas en ambas aurículas, que son también asequibles a tratamiento por ablación y que en el electrocardiograma son indistinguibles de una taquicardia focal. La ablación amplia de la aurícula izquierda para el tratamiento de la fibrilación auricular está dando lugar a un nuevo tipo de taquicardias reentrantes que puede ser problemático en el futuro. Las técnicas de mapeo y encarrilamiento de los circuitos descritas inicialmente en el flúter permiten definir estos circuitos. El mapeo electroanatómico, que construye moldes anatómicos virtuales de las aurículas, es de gran ayuda en estos casos. A pesar del éxito de la ablación, el pronóstico a largo plazo se ensombrece con frecuencia por la aparición de fibrilación auricular, lo que indica que hay un sustrato arritmogénico común al flúter y la fibrilación, que la ablación del istmo cavotricuspídeo no cambia. En contraste con la clara definición electrofisiológica, hay escasa información sobre el curso clínico del flúter, ya que tradicionalmente la bibliografía se refiere a grupos de «flúter y fibrilación auricular» y las complejas relaciones entre ambas arritmias quedan aún por revelar claramente. La prevención primaria y la prevención de la aparición de fibrilación auricular tras la ablación son retos pendientes (AU)

Invasive electrophysiologic studies have changed the clinical outlook for patients with atrial flutter. Recognition of the reentrant circuit responsible for typical atrial flutter has led to the development of catheter ablation techniques that can prevent recurrence in >90% of cases. In addition, general understanding of atrial tachycardias has changed radically, such that ECG-based classifications are now obsolete. Atypical reentrant circuits associated with surgical scars or fibrotic areas in either atrium, which are indistinguishable from focal tachycardias on ECG, have been identified. These circuits also seem amenable to treatment by ablation. Recently, a new type of reentrant tachycardia that could be problematic in the future has emerged in patients who have undergone extensive left atrial ablation for the treatment of atrial fibrillation. These atypical circuits can be characterized using the mapping and entrainment techniques initially developed for typical flutter. In these cases, electroanatomical mapping, involving the construction of a virtual anatomical model of the atria, is extremely helpful. Despite the success of ablation, long-term prognosis is frequently overshadowed by the appearance of atrial fibrillation, which suggests that flutter and fibrillation share a common arrhythmogenic origin that is not modified by cavotricuspid isthmus ablation. In contrast with our clear electrophysiologic understanding of atrial flutter, little is known about the natural history of the condition because the literature has traditionally grouped patients with flutter and fibrillation together. Consequently, the complex relationship between the two arrhythmias has still to be clearly delineated. Primary prevention and preventing the development of atrial fibrillation after ablation remain outstanding clinical challenges (AU)

Atrial activation mapping in sinus rhythm in the clinical electrophysiology laboratory: observations during Bachmann's bundle block.

INTRODUCTION: The high posterolateral right atrium (RA) is considered the "sinus node area," but we lack information on endocardial atrial activation in sinus rhythm. We studied RA and left atrial (LA) endocardial activation in the electrophysiology laboratory. METHODS AND RESULTS: Thirty-five patients (21 men) aged 47 +/- 16.4 years (mean +/- SD) underwent RA mapping (22.2 +/- 3.8 points). In 21 patients, LA activation was mapped (11.1 +/- 3.9 points) through the coronary sinus (CS), right pulmonary artery, and/or a patent oval foramen. Fourteen patients had atrial arrhythmias, and 3 an ECG pattern of Bachmann's bundle block. Endocardial RA activation preceded P wave in 5 (-14 +/- 4.2 ms), coincided in 11, and followed P onset in 18 (16.7 +/- 6.6 ms). Location of the zero point varied from the superior vena cava to the low RA and from lateral to paraseptal RA. In 19 patients, activation started simultaneously in 2 to 5 points located >or=1 cm apart. RA activation was descending in most, but in 3 with low onset there was collision in the anterior and septal walls. In 15 of 21 patients, descending LA activation dominated, ending in the mid CS in 12, proximal CS in 1, and simultaneously throughout the CS in 2. In 3 with Bachmann's bundle block, CS activation was ascending and in 2 double potentials were recorded from the LA roof. CONCLUSION: During stable sinus rhythm, RA activation can start in different areas or simultaneously over large areas resulting in different activation patterns, both in the RA and the LA. LA activation is predominantly descending, but in Bachmann's bundle block it becomes ascending, and double potentials suggest a location of block in the LA roof.

Atypical flutter: a review.

Understanding of typical flutter circuits led the way to the study of other forms of macroreentrant tachycardias of the atria, and to their treatment by catheter ablation. It has become evident that the ECG classification of atrial flutter and atrial tachycardia by a rate cutoff and the presence or absence of isoelectric baselines between atrial deflections is not a valid indicator of tachycardia mechanism. Macroreentrant circuits where activation rotates around large obstacles are the most common arrhythmias found in patients with atypical forms of flutter or atrial tachycardia, especially after surgery for congenital heart disease, however, focal mechanisms can also be found. Large areas of low voltage electrograms, suggestive of severe myocardial damage (fibrosis or infiltration) can be found in many atypical macroreentrant tachycardias at the center of the circuit. Many of these circuits can be mapped precisely, critical isthmuses can be defined, and effective catheter ablation can be performed. The need to match activation maps with anatomy precisely, makes computer assisted, anatomically precise mapping a useful tool. Entrainment techniques have to be used sparingly to avoid tachycardia interruption. In complex cases, ablation can be done in sinus rhythm, after definition of conducting channels between low voltage areas and scars or anatomic obstacles. Long-term prognosis is uncertain and depends on the underlying pathology.

Severe mitral regurgitation with right ventricular pacing, successfully treated with left ventricular pacing.

A case of severe mitral regurgitation with refractory heart failure, after atrioventricular junction ablation and pacemaker implant, was solved with left ventricular pacing. Mitral regurgitation was related to a change in segmental left ventricular motion during right ventricular pacing.

[Electrophysiological and clinical characterization of left atrial macroreentrant tachycardia]. / Caracterización electrofisiológica y clínica de la taquicardia macrorreentrante auricular izquierda.

BACKGROUND AND OBJECTIVE: We are reporting the characteristics of 9 patients with left atrial macroreentrant tachycardia, an arrhythmia not well studied in man. PATIENTS AND METHOD: Mean age was 60 years and 7 were men. Tachycardia was spontaneous in 6 and induced in 3. Two had no heart disease, 2 sick sinus syndrome, 3 aortic prosthesis, 2 hypertension, 1 cardiomyopathy and 1 chronic bronchitis. Simultaneous recordings from right atrial, coronary sinus and right pulmonary artery were obtained at baseline and with atrial pacing. Macroreentrant tachycardia was diagnosed when entrainment with fusion was documented. RESULTS: Cycle length was 230-440 ms (287 67). The ECG showed atypical flutter in 3 patients and P waves with flat baseline in 6. Coronary sinus activation was distal to proximal in 7. Right atrial activation was circular in 3 with previous typical flutter ablation. Entrainment from the right atrium produced long return cycles in the right atrial recordings, but equal to basal tachycardic cycle in coronary sinus recordings. Entrainment from the coronary sinus produced local return cycles equal to basal cycle in 8 and prolonged in 1. After stimulation, 4 recovered sinus rhythm, 4 went to atrial fibrillation and 1 had no change. After a follow-up of 9-19 months 5 remain in sinus rhythm treated with antiarrhythmic drugs and/or atrial pacing. CONCLUSIONS: Left atrial macroreentrant tachycardia is associated with organic heart disease. The ECG most frequent pattern tends to show P waves with flat baseline at a relatively slow rate. Most circuits turn clockwise in anterior view. Atrial stimulation is not very effective for cardioversion to sinus rhythm. The prognosis of long term rhythm is uncertain.

Caracterización electrofisiológica y clínica de la taquicardia macrorreentrante auricular izquierda / Electrophysiological and Clinical Characterization of Left Atrial Macroreentrant Tachycardia

Introducción y objetivos. Describimos las características de 9 pacientes con taquicardia macrorreentrante auricular izquierda, un tipo mal conocido de arritmia. Pacientes y método. La edad media de los pacientes era 60 años y siete eran varones. La taquicardia fue espontánea en 6 casos e inducida en tres. En 2 enfermos no había cardiopatía, tres tenían una prótesis aórtica, dos disfunción sinusal, dos hipertensión arterial, uno miocardiopatía dilatada y uno bronquitis crónica. Se obtuvieron registros simultáneos de la aurícula derecha, el seno coronario y la arteria pulmonar derecha. Se diagnosticó taquicardia macrorreentrante en presencia de encarrilamiento con fusión en los registros endocavitarios. Resultados. La longitud de ciclo era 230-440 ms (287 ñ 67) y el patrón de ECG de aleteo era atípico en 3 pacientes y onda P con línea isoeléctrica en seis. El seno coronario se activaba de distal a proximal en 7 casos. La activación de la aurícula derecha era circular en 3 enfermos con ablación previa de aleteo típico. El encarrilamiento desde la aurícula derecha puso de manifiesto pausas de retorno largas en los registros de la aurícula derecha e iguales al ciclo de la taquicardia en el seno coronario. El encarrilamiento desde el seno coronario evidenció una pausa local igual al ciclo basal en 8 pacientes y prolongada en uno. Con la estimulación, 4 enfermos pasaron a ritmo sinusal, cuatro a fibrilación auricular y uno no cambió. Un total de 5 pacientes se mantuvieron en ritmo sinusal entre 9-19 meses con fármacos antiarrítmicos y/o estimulación auricular. Conclusiones. La taquicardia macrorreentrante auricular izquierda se asocia a cardiopatía. El patrón más frecuente es de onda P con línea isoeléctrica y frecuencia relativamente lenta. La mayoría giran en sentido 'horario' en visión anterior. La estimulación es poco eficaz para restablecer el ritmo sinusal. El pronóstico del ritmo a largo plazo es incierto (AU)

Beneficio hemodinámico de la estimulación ventricular izquierda en dos síndromes de marcapasos con insuficiencia cardíaca refractaria / Hemodynamic benefits of lefft ventricular pacing in two pacemakers syndromes with refractoy heart failure

Presentamos 2 casos en los que la estimulación en el ventrículo derecho produjo un deterioro hemodinámico muy importante y en los que de forma aguda el cambio del sitio de estimulación del ventrículo derecho al ventrículo izquierdo corrigió estas alteraciones, mientras que no lo hacía la estimulación biventricular simultánea. La estimulación crónica del ventrículo izquierdo puede ser capaz de resolver las alteraciones hemodinámicas de los síndromes de marcapasos graves y puede evitar la necesidad de implantación de una prótesis mitral en algunos casos. La aplicación en el momento actual debe hacerse de forma individualizada, incluyendo estudio hemodinámico y ecocardiográfico agudo, ya que la anchura del complejo QRS durante la estimulación no es un índice significativo de eficacia hemodinámica (AU)

Taquicardia reentrante intranodal como inductora de fibrilación auricular / Atrioventricular nodal reentrant tachycardia as a trigger for atrial fibrillation

Presentamos el caso de un varón de 43 años con historia de palpitaciones paroxísticas de larga evolución autoyuguladas con maniobras vagales, donde la única arritmia documentada era fibrilación auricular. El estudio electrofisológico demostró la presencia de una taquicardia intranodal típica, que en segundos degeneraba en fibrilación auricular, reproduciendo la sintomatología arrítmica del paciente. Después de ablación mediante radiofrecuencia de la 'vía lenta', el paciente quedó sin taquicardia inducible y sin eventos arrítmicos posteriores durante un seguimiento de 20 meses. En pacientes seleccionados, el estudio electrofisiológico podría revelar causas curables de fibrilación auricular paroxística (AU)